Modeling of germanium/silicon interdiffusion in silicon/silicon germanium/silicon single quantum well structures

Purely substitutional diffusion equations were applied to model the interdiffusion of Si and Ge in Si/Si1-xGex/Si single quantum well structures grown by molecular beam epitaxy and annealed at 900°C, 1000°C and 1100°C for different times in inert and oxidizing ambients. Intrinsic diffusivities of Si and Ge as a function of Ge fraction in the structure used as the fitting parameters match values reported in the literature. Once these parameters were fixed for the inert ambient, the diffusion behavior under oxidizing conditions was completely accounted for by the model with no additional fitting parameters. Excellent fits were obtained in all the cases.